Microscopic Colitis Information

Microscopic colitis (MC) is inflammation of the bowel that is only visible using a microscope. The term bowel refers to any part of the small or large intestine. Colitis means inflammation of the colon. The large intestine includes the colon and the rectum that together are about five feet long. The small intestine can be 12-20 feet long.

MC is less severe than other types of inflammatory bowel disease (IBD) because it does not lead to cancer and rarely requires surgery. However, MC can cause considerable pain and discomfort.

Microscopic Colitis—Collagenous Colitis and Lymphocytic Colitis

MC has two main forms—collagenous colitis and lymphocytic colitis. The symptoms of and treatment for both are identical. Although it is believed that the two forms may be different presentations of the same disease, they differ in the way intestinal tissue appears when seen with a microscope. In both forms, an increase in white blood cells can be seen within the intestinal epithelium—the layer of cells that lines the intestine. Increased white blood cells are a sign of inflammation. With collagenous colitis, a layer of tissue called collagen appears thicker than normal beneath the epithelium.

MC can affect anyone but is more common in people of age 45 or older. Rates of MC are similar to other forms of IBD, affecting about nine people in 100,000. Although MC affects both men and women, collagenous colitis is much more common in women. There is a known association of microscopic colitis and celiac disease.

Common Symptoms:
Chronic non-bloody watery diarrhea is the main symptom of MC. Episodes of diarrhea can last for weeks, months, or years. Most cases are interrupted by similarly long periods of remission, i.e., periods when the diarrhea goes away. Other common symptoms of MC include:
• Abdominal cramps or pain
• Abdominal bloating

The cause of MC is unknown. However many scientists believe it is an abnormal immune response triggered by something interacting with the in the gastrointestinal (GI) tract— the large, muscular tube that extends from the mouth to the anus that digests food. Scientists believe one’s genes may make a person more likely to develop MC. Although a gene unique to MC has yet to be found, dozens have been linked to other forms of IBD.

Treatment Options:
People with MC generally achieve relief with treatment, although relapses can occur. Some patients require long-term therapy because they experience prompt relapses when treatment is stopped. Unlike IBD, MC usually does not result in other problems, such bowel obstruction or colon cancer.

Questions To Ask Your Healthcare Provider

• What treatment option is best for me?
• What are the potential side effects?
• What dietary or lifestyle changes do you recommend?

This information is intended for patient education and information only. It does not constitute advice, nor should it be taken to suggest or replace professional medical care from your physician. Your treatment options may vary, depending upon your medical history and current condition. Only your physician and you can determine your best treatment option.

College of American Pathologists
325 Waukegan Road
Northfield, IL 60093-2750
Phone: 800.323.4040
Please visit www.cap.org, from the cap home page, please click on “Health and Wellness Resources for the
Public”. The following options will appear on the Resources for the Public page:

2. Your Health: Your health test reminder – Patients can put in personal data and will get reminder emails for
important tests, screening colonoscopies, etc. Information on disease diagnosis and prevention – A page developed by pathologists, doctors who specialize in prevention, early detection, and diagnosis of disease.